blob: 4df58b8ea64a97d562f0701f4061152ed0f02fc2 [file] [log] [blame]
Eric Paris0d48b7f2009-12-17 21:24:27 -05001/*
2 * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2, or (at your option)
7 * any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; see the file COPYING. If not, write to
16 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19#include <linux/fs.h>
20#include <linux/init.h>
21#include <linux/kernel.h>
22#include <linux/module.h>
23#include <linux/mount.h>
24#include <linux/mutex.h>
Eric Paris0d48b7f2009-12-17 21:24:27 -050025#include <linux/spinlock.h>
Eric Paris0d48b7f2009-12-17 21:24:27 -050026
Arun Sharma600634972011-07-26 16:09:06 -070027#include <linux/atomic.h>
Eric Paris0d48b7f2009-12-17 21:24:27 -050028
29#include <linux/fsnotify_backend.h>
30#include "fsnotify.h"
Al Viroc63181e2011-11-25 02:35:16 -050031#include "../mount.h"
Eric Paris0d48b7f2009-12-17 21:24:27 -050032
33void fsnotify_clear_marks_by_mount(struct vfsmount *mnt)
34{
35 struct fsnotify_mark *mark, *lmark;
36 struct hlist_node *pos, *n;
Al Viroc63181e2011-11-25 02:35:16 -050037 struct mount *m = real_mount(mnt);
Eric Paris0d48b7f2009-12-17 21:24:27 -050038 LIST_HEAD(free_list);
39
40 spin_lock(&mnt->mnt_root->d_lock);
Al Viroc63181e2011-11-25 02:35:16 -050041 hlist_for_each_entry_safe(mark, pos, n, &m->mnt_fsnotify_marks, m.m_list) {
Eric Paris0d48b7f2009-12-17 21:24:27 -050042 list_add(&mark->m.free_m_list, &free_list);
Eric Parisa4c6e992010-07-28 10:18:38 -040043 hlist_del_init_rcu(&mark->m.m_list);
Eric Paris0d48b7f2009-12-17 21:24:27 -050044 fsnotify_get_mark(mark);
45 }
46 spin_unlock(&mnt->mnt_root->d_lock);
47
48 list_for_each_entry_safe(mark, lmark, &free_list, m.free_m_list) {
Lino Sanfilippoe2a29942011-06-14 17:29:51 +020049 struct fsnotify_group *group;
50
51 spin_lock(&mark->lock);
52 fsnotify_get_group(mark->group);
53 group = mark->group;
54 spin_unlock(&mark->lock);
55
56 fsnotify_destroy_mark(mark, group);
Eric Paris0d48b7f2009-12-17 21:24:27 -050057 fsnotify_put_mark(mark);
Lino Sanfilippoe2a29942011-06-14 17:29:51 +020058 fsnotify_put_group(group);
Eric Paris0d48b7f2009-12-17 21:24:27 -050059 }
60}
61
Eric Paris4d926042009-12-17 21:24:34 -050062void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group)
63{
64 fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_VFSMOUNT);
65}
66
Eric Paris0d48b7f2009-12-17 21:24:27 -050067/*
68 * Recalculate the mask of events relevant to a given vfsmount locked.
69 */
70static void fsnotify_recalc_vfsmount_mask_locked(struct vfsmount *mnt)
71{
Al Viroc63181e2011-11-25 02:35:16 -050072 struct mount *m = real_mount(mnt);
Eric Paris0d48b7f2009-12-17 21:24:27 -050073 struct fsnotify_mark *mark;
74 struct hlist_node *pos;
75 __u32 new_mask = 0;
76
77 assert_spin_locked(&mnt->mnt_root->d_lock);
78
Al Viroc63181e2011-11-25 02:35:16 -050079 hlist_for_each_entry(mark, pos, &m->mnt_fsnotify_marks, m.m_list)
Eric Paris0d48b7f2009-12-17 21:24:27 -050080 new_mask |= mark->mask;
Al Viroc63181e2011-11-25 02:35:16 -050081 m->mnt_fsnotify_mask = new_mask;
Eric Paris0d48b7f2009-12-17 21:24:27 -050082}
83
84/*
85 * Recalculate the mnt->mnt_fsnotify_mask, or the mask of all FS_* event types
86 * any notifier is interested in hearing for this mount point
87 */
88void fsnotify_recalc_vfsmount_mask(struct vfsmount *mnt)
89{
90 spin_lock(&mnt->mnt_root->d_lock);
91 fsnotify_recalc_vfsmount_mask_locked(mnt);
92 spin_unlock(&mnt->mnt_root->d_lock);
93}
94
95void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark)
96{
97 struct vfsmount *mnt = mark->m.mnt;
98
Lino Sanfilippo986ab092011-06-14 17:29:50 +020099 BUG_ON(!mutex_is_locked(&mark->group->mark_mutex));
Eric Paris0d48b7f2009-12-17 21:24:27 -0500100 assert_spin_locked(&mark->lock);
Eric Paris0d48b7f2009-12-17 21:24:27 -0500101
102 spin_lock(&mnt->mnt_root->d_lock);
103
Eric Parisa4c6e992010-07-28 10:18:38 -0400104 hlist_del_init_rcu(&mark->m.m_list);
Eric Paris0d48b7f2009-12-17 21:24:27 -0500105 mark->m.mnt = NULL;
106
107 fsnotify_recalc_vfsmount_mask_locked(mnt);
108
109 spin_unlock(&mnt->mnt_root->d_lock);
110}
111
112static struct fsnotify_mark *fsnotify_find_vfsmount_mark_locked(struct fsnotify_group *group,
113 struct vfsmount *mnt)
114{
Al Viroc63181e2011-11-25 02:35:16 -0500115 struct mount *m = real_mount(mnt);
Eric Paris0d48b7f2009-12-17 21:24:27 -0500116 struct fsnotify_mark *mark;
117 struct hlist_node *pos;
118
119 assert_spin_locked(&mnt->mnt_root->d_lock);
120
Al Viroc63181e2011-11-25 02:35:16 -0500121 hlist_for_each_entry(mark, pos, &m->mnt_fsnotify_marks, m.m_list) {
Eric Paris0d48b7f2009-12-17 21:24:27 -0500122 if (mark->group == group) {
123 fsnotify_get_mark(mark);
124 return mark;
125 }
126 }
127 return NULL;
128}
129
130/*
131 * given a group and vfsmount, find the mark associated with that combination.
132 * if found take a reference to that mark and return it, else return NULL
133 */
134struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group,
135 struct vfsmount *mnt)
136{
137 struct fsnotify_mark *mark;
138
139 spin_lock(&mnt->mnt_root->d_lock);
140 mark = fsnotify_find_vfsmount_mark_locked(group, mnt);
141 spin_unlock(&mnt->mnt_root->d_lock);
142
143 return mark;
144}
145
146/*
147 * Attach an initialized mark to a given group and vfsmount.
148 * These marks may be used for the fsnotify backend to determine which
149 * event types should be delivered to which groups.
150 */
151int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark,
152 struct fsnotify_group *group, struct vfsmount *mnt,
153 int allow_dups)
154{
Al Viroc63181e2011-11-25 02:35:16 -0500155 struct mount *m = real_mount(mnt);
Eric Paris0c6532e2010-07-28 10:18:38 -0400156 struct fsnotify_mark *lmark;
157 struct hlist_node *node, *last = NULL;
Eric Paris0d48b7f2009-12-17 21:24:27 -0500158 int ret = 0;
159
Eric Paris700307a2010-07-28 10:18:38 -0400160 mark->flags |= FSNOTIFY_MARK_FLAG_VFSMOUNT;
Eric Paris0d48b7f2009-12-17 21:24:27 -0500161
Lino Sanfilippo986ab092011-06-14 17:29:50 +0200162 BUG_ON(!mutex_is_locked(&group->mark_mutex));
Eric Paris0d48b7f2009-12-17 21:24:27 -0500163 assert_spin_locked(&mark->lock);
Eric Paris0d48b7f2009-12-17 21:24:27 -0500164
165 spin_lock(&mnt->mnt_root->d_lock);
166
Eric Paris0c6532e2010-07-28 10:18:38 -0400167 mark->m.mnt = mnt;
Eric Paris0d48b7f2009-12-17 21:24:27 -0500168
Eric Paris0c6532e2010-07-28 10:18:38 -0400169 /* is mark the first mark? */
Al Viroc63181e2011-11-25 02:35:16 -0500170 if (hlist_empty(&m->mnt_fsnotify_marks)) {
171 hlist_add_head_rcu(&mark->m.m_list, &m->mnt_fsnotify_marks);
Eric Paris0c6532e2010-07-28 10:18:38 -0400172 goto out;
Eric Paris0d48b7f2009-12-17 21:24:27 -0500173 }
174
Eric Paris0c6532e2010-07-28 10:18:38 -0400175 /* should mark be in the middle of the current list? */
Al Viroc63181e2011-11-25 02:35:16 -0500176 hlist_for_each_entry(lmark, node, &m->mnt_fsnotify_marks, m.m_list) {
Eric Paris0c6532e2010-07-28 10:18:38 -0400177 last = node;
178
179 if ((lmark->group == group) && !allow_dups) {
180 ret = -EEXIST;
181 goto out;
182 }
183
Eric Paris6ad2d4e2010-10-28 17:21:56 -0400184 if (mark->group->priority < lmark->group->priority)
185 continue;
186
187 if ((mark->group->priority == lmark->group->priority) &&
188 (mark->group < lmark->group))
Eric Paris0c6532e2010-07-28 10:18:38 -0400189 continue;
190
Eric Parisa4c6e992010-07-28 10:18:38 -0400191 hlist_add_before_rcu(&mark->m.m_list, &lmark->m.m_list);
Eric Paris0c6532e2010-07-28 10:18:38 -0400192 goto out;
193 }
194
195 BUG_ON(last == NULL);
196 /* mark should be the last entry. last is the current last entry */
Eric Parisa4c6e992010-07-28 10:18:38 -0400197 hlist_add_after_rcu(last, &mark->m.m_list);
Eric Paris0c6532e2010-07-28 10:18:38 -0400198out:
199 fsnotify_recalc_vfsmount_mask_locked(mnt);
Eric Paris0d48b7f2009-12-17 21:24:27 -0500200 spin_unlock(&mnt->mnt_root->d_lock);
201
202 return ret;
203}